18 Mr. De la Beche on the Geology of Southern Pembrokeshire. 



Mynwer, on old red sandstone : and from Newton Quarries to the cove 

 between Pendine Cliffs and Marcroes Mountain, on carboniferous limestone. 

 The coal-measures are bounded on the south, at Gouldtrop Road in St. Bride's 

 Bay, by a thin stratum of carboniferous limestone, which in.tervenes between 

 them and the trap : from Rosepool to Walwin's Castle and Tiers Cross, by a 

 narrow dyke of trap, which separates them from old red sandstone : from 

 Tiers Cross to Anneykell and Bolton Farms, by the trap of Bolton Beacon : 

 at Johnston, by carboniferous limestone interposed between them and the 

 trap : at Craneham, Clarisson, and Nash, by trap-rocks : at Langum, by old red 

 sandstone : and from Langum Perry to Tenby, by carboniferous limestone. 

 Excepting along the eastern portion of their northern boundary, these coal- 

 measures have been greatly disturbed. Their contortions may be seen in St. 

 Bride's Bay at the cliffs extending from the hill north of Broadhaven to Gould- 

 trop Road, where as they approach the trap they are most curiously twisted 

 (see PI. II. fig. 2.) ; and in Caermarthen Bay at the cliffs extending from 

 Tenby to Sandersfoot (see PL II. fig. 6.). The most remarkable contor- 

 tions are at Monk's Stone Point near Tenby, represented in the adjoining 

 figure. 



Stone-coal, or culm, is the only variety of coal that occurs in Pembrokeshire, 

 bituminous coal being altogether wanting in the district. The beds of stone- 

 coal usually worked will be seen in the following section of the collieries 

 belonging to I. M. Child, Esq. at Begelly, a village situate nearly midway 

 between the southern and northern boundaries of the basin, on the road from 

 Tenby to Narberth. The dip is to the south-west or south-south-west, at 

 about one in three. 



